The present invention relates to a new and improved construction of gas filter element for gas cleaning, which is of the type comprising a substantially wedge-shaped filter pocket containing side walls formed of a filter material and a number of areal or surface-like flexible spacer holders, which may be of a given geometric configuration, such as triangular- or trapezoidal-shaped, arranged to extend approximately in the direction of gas flow transverse to the side walls and are connected along lengthwise edges thereof with the side walls. The invention also is concerned with a method of manufacturing the gas filter elements of the invention.
Gas filter elements of this general type usually possess spacer holders composed of blanks. According to one of the prior art gas filter elements the spacer holders are designed as double-wall trapezoidal blanks and are connected with the pocket walls by an adhesive bond or welding.
Particularly as concerns the fabrication of the spacer holders or spacers, the state-of-the-art gas filter elements are not totally satisfactory. In order to produce the blanks, for instance in a trapezoidal-shaped configuration, there are required correspondingly expensive cutting devices if there is to be realized any rational production.
If the spacer holders are to be structured as double-wall elements, then an additional operation and expenditure is needed for welding or heat sealing the blanks, increasing the manufacturing costs.